Apparatus and method for manufacturing an optical fiber ribbon

ABSTRACT

An assembly for fabricating an optical fiber ribbon from optical fibers that extend in a longitudinal direction includes a spacing device. The spacing device is operative to vary the spacing between the optical fibers in the lateral direction. The spacing device can be a rotatable cylinder having diverging external grooves that respectively receive the optical fibers. A bonding device applies bonding material to the optical fibers to form an optical fiber ribbon, after the spacing between the optical fibers has been varied by the spacing device. In accordance with a method of manufacturing an optical fiber ribbon, optical fibers that extend in a longitudinal are advanced along travel paths defined by the grooves of the spacing guide. The travel paths diverge from one another in a lateral direction that is generally perpendicular to the longitudinal direction so that as the optical fibers are advanced the optical fibers become further spaced apart from one another in the lateral direction. The increased spacing between the optical fibers is maintained by bonding the optical fibers together.

FIELD OF THE INVENTION

The present invention relates to optical fiber ribbons and, moreparticularly, to the spacing between optical fibers of optical fiberribbons.

BACKGROUND OF THE INVENTION

Optical fiber is a very popular medium for large bandwidth applications,and as a result there is a demand for increased numbers of opticalfibers. In response to these demands, optical fiber ribbons have beendeveloped. An optical fiber ribbon includes a planar array of opticalfibers that extend longitudinally and are laterally adjacent, and theoptical fibers are bonded together as a unit.

It is conventional for adjacent optical fibers of an optical fiberribbon to be in an abutting side-by-side arrangement. As a result, thespacing between adjacent optical fibers in an optical fiber ribbon isoften less than the spacing between adjacent optical receptacles ofoptical devices that optically communicate with the optical fiberribbon. Optical devices that optically communicate with an optical fiberribbon include optical input or output devices, which respectivelyintroduce optical signals into or receive optical signals from theoptical fibers of optical fiber ribbon. It is common to prepare anoptical fiber ribbon for attachment to the optical receptacles of anoptical input or optical output device by striping the bonding materialof the optical fiber ribbon away from one end of the optical fiberribbon. A sufficient amount of the bonding material is stripped away sothat exposed ends of the optical fibers can be manually spaced apartfrom one another and be respectively received by the receptacles of thetarget optical device.

Often it is necessary for relatively long lengths of optical fibers tobe exposed at the end of an optical fiber ribbon to obtain the spacingnecessary to connect to the relatively far spaced apart receptacles ofthe target optical device. The binding material that holds the opticalfibers of an optical fiber ribbon together provides some protection tothe optical fibers; therefore, the optical fibers that are exposed bythe stripping are at a relatively greater risk of being damaged. Inaddition, long lengths of loose optical fibers that extend from anoptical fiber ribbon are at risk of becoming tangled and disorganized,and can be difficult to manually manage. These risks or disadvantagesare becoming greater and greater as optical fibers and associatedequipment become more densely packaged in response to the increasingdemand for optical fibers.

SUMMARY OF THE INVENTION

The present invention provides methods and apparatus for manufacturingoptical fiber ribbons and, more specifically, for manufacturingmultipitch optical fiber ribbons.

In accordance with one aspect of the present invention, an assembly forfabricating an optical fiber ribbon from optical fibers that extend in alongitudinal direction is provided. The assembly includes a spacingdevice having spacing guides that are spaced apart from one another in alateral direction that is generally perpendicular to the longitudinaldirection. Each spacing guide is operative for respectively receivingand guiding an optical fiber of the optical fibers. The spacing deviceis operative to vary the spacing between the spacing guides in thelateral direction. The assembly may further include a moving device foradvancing the optical fibers generally in the longitudinal directionthrough their respective spacing guides so that the spacing of thespacing guides is imparted upon portions of the optical fibers that aredownstream from the spacing guides. The assembly may further include abonding device positioned downstream from the spacing guides andoperative for applying bonding material to the portions of the opticalfibers that are downstream from the spacing guides. The bonding materialbonds the portions of the optical fibers that are downstream from thespacing guides together to form an optical fiber ribbon.

In accordance with one aspect of the present invention, the spacingguide includes a wall that extends generally arcuately about an axisthat extends generally in the lateral direction. The wall furtherextends generally in the lateral direction and includes an outer surfacethat generally extends generally arcuately about the axis and in thelateral direction. The wall defines grooves that are open at the outersurface and extend generally arcuately about the axis, and portions ofthe grooves function as the spacing guides. The grooves are spaced apartfrom one another in the lateral direction, and the spacing between thegrooves varies with respect to an arcuate direction that is definedabout the axis. Those grooves are relatively narrow grooves thatoriginate from a relatively wide groove that is also open at the outersurface and extends generally arcuately about the axis. The narrowgrooves diverge Is they extend generally in the arcuate direction awayfrom the wide groove.

In accordance with another aspect of the present invention, the assemblyfor fabricating an optical fiber ribbon includes a frame, and thespacing guide is pivotally connected to the frame for pivoting about theaxis. The fabricating assembly optionally includes a cross member thatis movably mounted to the frame and can be positioned in close proximityto the outer surface of the spacing guide. The cross member can extendgenerally in the lateral direction across the grooves so that the crossmember cooperates with the grooves to define spacing apertures thatrespectively receive the optical fibers. The spacing guide can includemarks that can be aligned with the cross member to define intervalsalong the grooves in the arcuate direction.

In accordance with another aspect of the present invention, a method ofmanufacturing an optical fiber ribbon is provided. In accordance withone example of the method, the optical fibers are advanced alongdiverging travel paths defined by the grooves of the spacing guide. Asthe optical fibers are advanced the optical fibers become further spacedapart from one another in the lateral direction. In accordance with oneexample, the advancing of the optical fiber ribbons along the travelpaths is facilitated by moving the spacing guide relative to the opticalfibers. More specifically, the advancing of the optical fiber ribbons isfacilitated by rotating the spacing guide about an axis. The increasedspacing between the optical fibers is maintained by bonding the opticalfibers together. The increased spacing between the optical fibers can beestablished over a long length of the optical fibers by establishingtranslational movement between the optical fibers and the spacing guide.

In accordance with another aspect of the present invention, bindingmaterial is removed from an optical fiber ribbon to expose portions ofthe optical fibers of the optical fiber ribbon. The exposed portions ofthe optical fibers are advanced along the diverging travel paths and arethereafter bonded together to provide a multipitch optical fiber ribbon.As one example, the multipitch optical fiber ribbon includes opticalfibers that extend longitudinally and are laterally adjacent. Theoptical fibers are bonded together by bonding material having oppositefirst and second ends. A lateral first spacing is defined betweenadjacent optical fibers at the first end of the bonding material, alateral second spacing is defined between adjacent optical fibers at thesecond end of the bonding material, and the first spacing is differentfrom the second spacing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a multipitch optical fiber ribbonconnected between optical devices in accordance with a first embodimentof the present invention.

FIG. 2 is an isolated, schematic cross-sectional view of the multipitchoptical fiber ribbon of FIG. 1 taken along line 2—2 of FIG. 1.

FIG. 3 is an isolated, schematic cross-sectional view of the multipitchoptical fiber ribbon of FIG. 1 taken along line 3—3 of FIG. 1.

FIG. 4 is a top plan view of a guide cylinder that is part of afabricating assembly for manufacturing the multipitch optical fiberribbon of FIG. 1, in accordance with the first embodiment of the presentinvention.

FIG. 5 is a schematic end elevation view of the guide cylinder of FIG.4.

FIG. 6 is a schematic view of the fabricating assembly for forming themultipitch optical fiber ribbon of FIG. 1, wherein the fabricatingassembly is partially set up for operation and includes the guidecylinder of FIGS. 4 and 5, in accordance with the first embodiment ofthe present invention.

FIG. 7 is a schematic, partial cross-sectional view taken along line A—Aof FIG. 6 with the guide cylinder in a first configuration, inaccordance with the first embodiment of the present invention.

FIG. 8 is a schematic, partial cross-sectional view taken along line A—Aof FIG. 6 with the guide cylinder in a second configuration, inaccordance with the first embodiment of the present invention.

FIG. 9 is a schematic, partial cross-sectional view taken along line A—Aof FIG. 6 with the guide cylinder in a third configuration, inaccordance with the first embodiment of the present invention.

FIG. 10 is a schematic, partial cross-sectional view taken along lineA—A of FIG. 6 with the guide cylinder in a fourth configuration, inaccordance with the first embodiment of the present invention.

FIG. 11 is a schematic view of the fabricating assembly of FIG. 6 inoperation, in accordance with the first embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

FIG. 1 illustrates a multipitch optical fiber ribbon 20 extending in alongitudinal direction between and connected between an optical device22 and an optical device 24, in accordance with a first embodiment ofthe present invention. Each of the optical devices 22, 24 can be a widevariety of different optical devices, such as optical transmitters thattransmit optical signals into optical fibers and optical receivers thatreceive optical signals from optical fibers. More specifically, theoptical devices 22, 24 can include optical/electromechanical systems orswitches, optical cross connects, and a wide variety of other types ofoptical devices that connect to and optically communicate with an arrayof optical fibers.

In accordance with the first embodiment, the multipitch optical fiberribbon 20 includes a relatively narrow section 26 having oppositerelatively narrow ends 28, 29, and a relatively wide section 30 havingopposite relatively wide ends 32, 33. In accordance with the firstembodiment, the narrow section 26 in isolation is a conventional opticalfiber ribbon; therefore, at times the terms narrow section 26 andconventional fiber ribbon 26 are used interchangeably when describingthe first embodiment. It is preferred for the multipitch optical fiberribbon 20 to be generally planar, yet flexible enough so that it can bemanually bent into a variety of curved shapes so that it can be routedaround various obstacles, or the like.

As illustrated in FIG. 1, receptacles of an array of receptacles 38 ofthe optical device 22 are respectively in receipt of the ends of theoptical fibers 36 that extend from the narrow end 28, and receptacles 40of the optical device 24 are respectively in receipt of the ends of theoptical fibers 36 that extend from the wide end 33. As will be discussedin greater detail below, different spacing between the optical fibers 36at the differently sized ends 28, 33 allows the multipitch optical fiberribbon 20 to be conveniently and efficiently connected between the arrayof receptacles 38 and the receptacles 40, which are spaced differently.

The multipitch optical fiber ribbon 20 include's a laterally extendingarray 34 of longitudinally extending optical fibers 36 that extendbetween the narrow end 28 and the wide end 33. Each of the opticalfibers have opposite ends that respectively protrude from the narrow end28 and the wide end 33. The optical fibers 36 are laterally adjacent andare held together by bonding material 42, 44. In FIG. 1, the centerlinesof the portions of the optical fibers 36 that are embedded in thebonding material 42, 44 are illustrated by dashed lines that extendbetween the narrow end 28 and the wide end 33. In accordance with thefirst embodiment, the array 34 is absent of splices between the opticalfibers 36 between the narrow end 28 and the wide end 33, and none of theoptical fibers cross one another between the narrow end 28 and the wideend 33.

A relatively small separation spacing “S1” is defined between thecenterlines of adjacent optical fibers 36 in the narrow section 26 ofthe multipitch optical fiber ribbon 20, and the separation spacing S1 isapproximately the same as the spacing between adjacent receptacles ofthe array of receptacles 38 of the optical device 22. A relatively largeseparation spacing “S2” is defined between the centerlines of adjacentoptical fibers 36 in the wide section 30 of the multipitch optical fiberribbon 20, and the separation spacing S2 is approximately the same asthe spacing between the adjacent receptacles 40 of the optical device24. The separation spacing S2 is greater than the separation spacing S1,as will be discussed in greater detail below. The spacing betweenoptical fibers of an optical fiber ribbon is often referred to as pitch.Accordingly, the optical fiber ribbon of the first embodiment isreferred to as the multipitch optical fiber ribbon 20 because it hasmore than one pitch. In addition, the narrow section 26 of themultipitch optical fiber ribbon 20 defines a relatively small width “W1”that is smaller than a relatively large width “W2” defined by the widesection 30 of the multipitch optical fiber ribbon 20.

In accordance with the first embodiment, in the narrow section 26 of themultipitch optical fiber ribbon 20 the optical fibers 36 are heldtogether by a homogeneous bonding material 42 that extends between theopposite narrow ends 28, 29. The homogeneous bonding material 42 is bestseen in FIG. 2, which is a schematic cross-sectional view of the narrowsection 26 of the multipitch optical fiber ribbon 20 taken along line2—2 of FIG. 1. FIG. 2 and all other cross-sectional views are schematicbecause, for example, it is preferred for each of the optical fibers 36to be conventional coated glass fibers, but the coatings are notdistinguished from the glass fibers in the figures.

In accordance with the first embodiment, the homogeneous bondingmaterial 42 is preferably a polymeric bonding material, and anacceptable design for the narrow section 26 of the multipitch opticalfiber ribbon 20 is described in U.S. Pat. No. 4,900,126, which isincorporated herein by reference. Briefly, the homogeneous bondingmaterial 42 is preferably an ultraviolet-curable matrix bondingmaterial, or the like. The homogeneous bonding material 42 materialfills the interstices between the optical fibers 36, binds together theoptical fibers, and extends to the outside boundary of the narrowsection 26 of the multipitch optical fiber ribbon 20.

A known ultraviolet-curable matrix material from which the homogeneousbonding material 42 is acceptably formed includes a resin, a diluent anda photoinitiator. The resin may include a diethylenic-terminated resinsynthesized from a reaction of hydroxy-terminated alkyl acrylate withthe reaction product of a polyester of polyethyl polyol of molecularweight of 1,000 to 6,000 with an aliphatic or aromatic diisocyanate, ordiethylenic-terminated resin synthesized from the reaction of glycidylacrylate with a carboxylic-terminated polymer or polyether of molecularweight 1,000 to 6,000. The diluent may include monofunctional ormultifunctional acrylic acid esters having a molecular weight of 100 to1,000 or N-vinylpyrrolidinone. For the photoinitiator, the compositionmay include ketonic compounds such as diethoxyacetophenone,acetophenone, benzophenone, benzoin, anthraquinone, and benzil dimethylketal. In a typical composition, the bonding matrix may include a resin(50-90%), diluents (5-40%), and a photoinitiator (1-10%). Allpercentages are by weight unless otherwise noted.

In accordance with the first embodiment, in the wide section 30 of themultipitch optical fiber ribbon 20 the optical fibers 36 are heldtogether by a composite bonding material 44 that extends between theopposite wide ends 32, 33. The composite bonding material 44 is bestseen in FIG. 3, which is a schematic cross-sectional view of the widesection 30 of the multipitch optical fiber ribbon 20 taken along line3—3 of FIG. 1. In accordance with the first embodiment, the compositebonding material 44 includes longitudinally extending pieces of tape 46that are positioned on opposite sides of the optical fibers 36. Thecomposite bonding material 44 further includes adhesive 48 that ispositioned between the inner surfaces of the tapes 46 and extends intothe interstices between the optical fibers 36. The adhesive 48preferably originates as backings on the inside surfaces of the tapes46.

As will be discussed in greater detail below, in accordance with thefirst embodiment, the wide section 30 of the multipitch optical fiberribbon 20 is preferably constructed using a fabricating assembly 70(FIGS. 1 and 11). Central to the fabricating assembly is a spacingdevice that can be referred to as a spacing guide member, and inaccordance with the first embodiment the spacing guide member is in theform of a guide cylinder 50, which is illustrated in FIGS. 4 and 5. Inaccordance with the first embodiment, it is preferred for the spacingguide member to have some arcuate characteristics, but it is notnecessary for the spacing guide member to be cylindrical.

As best understood with reference to FIG. 4, in accordance with thefirst embodiment the guide cylinder 50 includes generally circularopposite ends 52, 54. The guide cylinder 50 further includesa.cylindrical wall that includes an outer cylindrical surface 56. Theouter surface 56 extends laterally between the opposite ends 52, 54 andextends arcuately around an axis that is concentric with an axle 58about which the guide cylinder 50 can rotate.

Defined in the guide cylinder 50 are multiple narrow guide grooves 60a-f that diverge from a wide guide groove 62. Each of the grooves 60a-f, 62 are open at the outer surface 56 and extend arcuately partiallyaround the axle 58. Although the guide cylinder 50 is described asincluding six narrow guide grooves 60 a-f and the multipitch opticalfiber ribbon 20 (FIG. 1, 2, and 3) is described as including six opticalfibers 36 (FIGS. 1-3), it is within the scope of the present inventionfor the guide cylinder to include a greater or lesser number of narrowguide grooves and for the multipitch optical fiber ribbon to include agreater or lesser number of optical fibers.

In accordance with the first embodiment, a series of marks 64 aredefined across the outer surface 56 of the guide cylinder 50. The seriesof marks 64 is illustrated and described as including a Roman number Imark, Roman number II mark, Roman number III mark, and Roman number IVmark that designate intervals along the grooves 60 a-f, 62 in thearcuate direction. The series of marks 64 can incorporate a wide varietyof different indicia for designating different intervals along thegrooves 60 a-f, 62.

As will be discussed in greater detail below with reference to FIGS.7-10, the wide guide groove 62 defines a width “W3”, the narrow guidegrooves 60 a-f define a width “W4”, and each of those grooves define adepth “D”. As best understood with reference to FIG. 4 and FIG. 5, inwhich the wide guide groove 62 and the narrow guide groove 60 a areshown by broken lines, the depth of each of the grooves 60 a-f, 62 isuniform along the length of the groove, except as noted. Morespecifically, the depths of the narrow guide grooves 60 a-f taper tozero just past the Roman number IV mark in the direction away from theRoman number III mark. In addition, the depth of the wide guide groove62 tapers to zero just past the Roman number I mark in the directionaway from the Roman number II mark. As illustrated in FIG. 4, the widthof each of the grooves 60 a-f, 62 is uniform along the length thereof.In addition, edges 66 that define the transition between the wide guidegroove 62 and the narrow guide grooves 60 a-f are smooth and slightlyrounded to facilitate smooth passage of the optical fibers 36 (FIGS.1-3) from the wide guide groove to the narrow guide grooves, as will bediscussed in greater detail below.

FIG. 6 illustrates the fabricating assembly 70 partially set up forfabricating the multipitch optical fiber ribbon 20 (FIG. 1) from aconventional optical fiber ribbon 26 having an exposed array 34 ofoptical fibers 36 (FIG. 1) extending therefrom, in accordance with thefirst embodiment. In accordance with one method of the presentinvention, it is preferred for a portion of the binder material 42 (FIG.2) to be stripped from an end of an isolated conventional optical fiberribbon 26 to expose the array 34 of optical fibers 36, and thereafterfor the multipitch optical fiber ribbon 20 to be formed therefrom, asdescribed below.

In accordance with the first embodiment, the fabricating assembly 70includes a frame 72, which is illustrated by broken lines, that carriesthe opposite ends of the axle 58 of the guide cylinder 50 (also seeFIGS. 4 and 5). In accordance with the first embodiment, the frame 72optionally carries a cross member 74 that is moveable between a remoteposition that is illustrated by dashed lines and a proximate positionthat is illustrated by solid lines in FIG. 6. The cross member 74 isdistant from the guide cylindrical 50 while in the remote position. Incontrast, the cross member 74 is in close proximity to the apex of theouter surface 56 of the guide cylinder 50 while in the proximateposition. Depending upon the rotational position of the guide cylinder50 about the axle 58, the cross member 74 can extend laterally acrossthe grooves 60 a-f, 62 (FIGS. 4 and 5) while in the proximate position,as will be discussed in greater detail below.

In accordance with the first embodiment, the frame 72 is moveable andthe movability is acceptably facilitated, in part, by a pair of wheels81 that travel along a track 83, all of which is illustrated by brokenlines in FIG. 6. More specifically, the frame 72 is movable in adirection between a downstream holding device 88 and an upstream holdingdevice 84. The upstream holding device 84 is a gripping or clampingdevice that holds the free end of the exposed array 34 of optical fibers36. Preferably the upstream holding device 84 is equipped with atensioning mechanism 86, such as a pair of springs, or the like, thatmaintains a desired tension on the exposed array 34 as it is acted upon,as will be discussed in greater detail below. The downstream holdingdevice 88 is a gripping or clamping device that holds the end of theconventional optical fiber ribbon 26.

In accordance with the first embodiment, a pair of tape applicationassemblies 76 are positioned on opposite sides of the conventionaloptical fiber ribbon 26 and are carried by the frame 72. The tapeapplication assemblies 76 are operative for applying the compositebonding material 44 (FIG. 3) to the exposed array 34 of optical fibers36. The tape application assemblies 76 are positioned remotely from theconventional optical fiber ribbon 26 in FIG. 6. In accordance with thefirst embodiment, the frame 72 includes mechanisms (not shown) formoving the tape application assemblies 76 from their remote positionsillustrated in FIG. 6 to positions in which the tape applicationassemblies are more proximate to the exposed array 34 of optical fibers36.

As illustrated in FIG. 6, in accordance with the first embodiment, eachtape application assembly 76 acceptably includes a roll 78 of tape andan applicator roller 82, or the like. For each tape application assembly76, the tape 80 is preferably in the form of a tape 46 (FIG. 3), such asa conventional water-blocking tape, that is backed on one side withadhesive 48 (FIG. 3). In accordance with an alternative embodiment, theadhesive 48 is applied to the exposed array 34 of optical fibers 36 andthereafter the tape 46 is applied to the combination of the adhesive andthe exposed array of optical fibers. In accordance with this alternativeembodiment, the adhesive can be applied by spraying or other coatingtechniques.

The frame 72, wheels 81, and track 83 are illustrated in broken lines inFIG. 6 because in accordance with the first embodiment a variety ofdifferent frames and moving mechanisms therefor are suitable forcarrying out the movement operations of the present invention. Forexample, in accordance with one embodiment of the present invention theframe 72, wheels 81, and track 83 are not required. As one example, theguide cylinder 50 can be a handheld device that is manually moved alongthe exposed array 34 of optical fibers 36 and the tape 80 can bemanually applied to the exposed array of optical fibers without usingthe specifically illustrated tape application assemblies 76.

Referring to FIGS. 4 and 6, operations of the fabricating assembly 70will be described in accordance with the first embodiment. Thefabricating assembly 70 is set up for operation by having the crossmember 74 in its remote position, which is illustrated by broken linesin FIG. 6, and rotating the guide cylinder 50 about its axle 58 so thatthe Roman number I mark is at the apex of the outer surface 56 of theguide cylinder. Thereafter, an end of the conventional optical fiberribbon 26 is connected to the downstream holding device 88 and theexposed array 34 of optical fibers 36 extending from the conventionaloptical fiber ribbon 26 is connected to the upstream holding device 84so that the array passes through the portion of the wide guide groove 62(FIGS. 4 and 5) that is at the apex of the outer surface 56 of the guidecylinder 50. Then the cross member 74 is moved to its proximateposition, at which time the fabricating assembly 70 can be characterizedas being in a first configuration. In the first configuration, a portionof the exposed array 34 of optical fibers 36 extends through at least aportion of the wide guide groove 62 and the Roman number I mark isaligned with the cross member.

FIG. 7 is a partial, schematic cross-sectional view taken along line A—Aof FIG. 6 with the fabricating assembly 70 in the first configuration,in accordance with the first embodiment. As best seen in FIG. 7 and asmentioned above, the wide guide groove 62 defines a width W3 and a depthD. The width W3 is slightly greater than the number of optical fibers 36within the wide guide groove 62 multiplied by the diameter of thoseoptical fibers. The depth D that is slightly greater than the diameterof the optical fibers 36. Like in the narrow section 26 (FIGS. 1 and 2)of the multipitch optical fiber ribbon 20 (FIGS. 1 and 2), approximatelythe separation spacing S1 is defined between the centers of the portionsof adjacent optical fibers 36 illustrated in FIG. 7. In accordance withthe first embodiment, each of the optical fibers has a diameter ofapproximately 250 microns, and in FIG. 7 the sides of adjacent opticalfibers 36 are abutting one another, so that the separation spacing S1 isapproximately 250 microns.

From the viewpoint of FIG. 6, while the fabricating assembly 70 is inthe first configuration, which is illustrated in FIG. 7, the spacingbetween the portions of the optical fibers 36 (FIG. 7) engaged by theguide cylinder 50 can be gradually increased in a consistent andcontrolled manner by rotating the guide cylinder 50 counterclockwiseabout its axle 58. More specifically, the guide cylinder 50 can berotated counterclockwise about its axle 58, so that the Roman number IImark, Roman number III mark, or Roman number IV mark (FIG. 4) is alignedwith and in contact with the bottom surface of the cross member 74. Asthe guide cylinder 50 is rotated counterclockwise, relative motionoccurs between the portions of the optical fibers 36 engaged by theguide cylinder 50 and the narrow guide grooves 60 a-f. As will becomeapparent, the guide grooves 60 a-f respectively define travel paths, andas the guide cylinder 50 is rotated the optical fibers 36 respectivelyadvance along those travel paths such that the optical fibers becomefurther laterally spaced apart.

As best understood with reference to FIGS. 4 and 6, by having thefabricating assembly 70 in the first configuration, which is illustratedin FIG. 7, and then rotating the guide cylinder 50 counterclockwiseabout its axle 58 so that the Roman number II mark is aligned with andin contact with the bottom surface of the cross member 74, a secondconfiguration is achieved. The second configuration is characterized bya portion of the exposed array 34 of optical fibers 36 extending throughrespective portions of the narrow guide grooves 60 a-f and the Romannumber II mark being aligned with the cross member 74.

FIG. 8 is a partial, schematic cross-sectional view taken along line A—Aof FIG. 6, with the fabricating assembly 70 in the second configuration.Like in the wide section 30 (FIGS. 1 and 2) of the multipitch opticalfiber ribbon 20 (FIG. 1), approximately the separation spacing S2 isdefined between the centers of each of the portions of the adjacentoptical fibers 36 illustrated in FIG. 8. Likewise, approximately theseparation spacing S2 is defined between the centers of the portions ofeach of the adjacent narrow guide grooves 60 a-f illustrated in FIG. 8.In accordance with the first embodiment, the separation spacing S2 is atleast approximately twice as great as the separation spacing S1 (FIGS.1, 2, and 7), and more specifically the separation spacing S2 isapproximately 500 microns.

As best understood with reference to FIGS. 4 and 6, by having thefabricating assembly 70 in the first configuration, which is illustratedin FIG. 7, and then rotating the guide cylinder 50 counterclockwiseabout its axle 58 so that the Roman number III mark is aligned with andin contact with the bottom surface of the cross member 74, a thirdconfiguration is achieved. The third configuration is characterized by aportion of the exposed array 34 of optical fibers 36 extending throughrespective portions of the narrow guide grooves 60 a-f and the Romannumber III mark being aligned with the cross member 74.

FIG. 9 is a partial, schematic cross-sectional view taken along line A—Aof FIG. 6, with the fabricating assembly 70 in the third configuration.A separation spacing “S3” is defined between the centers of each of theportions of the adjacent optical fibers 36 illustrated in FIG. 9.Likewise, approximately the separation spacing S3 is defined between thecenters of each of the portions of the adjacent narrow guide grooves 60a-f illustrated in FIG. 9. In accordance with the first embodiment, theseparation spacing S3 is at least approximately three times greater thanthe separation spacing S1 (FIGS. 1, 2, and 7), and more specifically theseparation spacing S3 is approximately 750 microns.

As best understood with reference to FIGS. 4 and 6, by having thefabricating assembly 70 in the first configuration, which is illustratedin FIG. 7, and then rotating the guide cylinder 50 counterclockwiseabout its axle 58 so that the Roman number IV mark is aligned with andin contact with the bottom surface of the cross member 74, a fourthconfiguration is achieved. The fourth configuration is characterized bya portion of the exposed array 34 of optical fibers 36 extending throughrespective portions of the narrow guide grooves 60 a-f and the Romannumber IV mark being aligned with the cross member 74.

FIG. 10 is a partial, schematic cross-sectional view taken along lineA—A of FIG. 6, with the fabricating assembly 70 in the fourthconfiguration. A separation spacing “S4” is defined between the centersof each of the portions of the adjacent optical fibers 36 illustrated inFIG. 10. Likewise, approximately the separation spacing S4 is definedbetween the centers of each of the portions of the adjacent narrow guidegrooves 60 a-f illustrated in FIG. 9. In accordance with the firstembodiment, the separation spacing S4 is at least approximately fourtimes greater than the separation spacing S1 (FIGS. 1, 2, and 7), andmore specifically the separation spacing S4 is approximately 1000microns.

As best seen in FIGS. 8-10 and as mentioned above, each of the narrowguide grooves 60 a-f defines a width W4 and the above-discussed depth D.The width W4 is slightly greater than the diameter of the optical fibers36.

In accordance with the first embodiment, in each of the first throughfourth configurations respectively illustrated by FIGS. 7-10, theoptical fibers 36 extend in a plane that is approximately tangent to theinnermost surfaces of the guide cylinder 50 that define the respectivegroove(s) 60 a-f, 62 so that only small arcuate lengths of therespective groove(s) are occupied at any time by the optical fibers 36.Accordingly, in each of the second through fourth configurationsrespectively illustrated by FIGS. 8-10, only a small arcuate length ofeach of the narrow guide grooves 60 a-f is occupied at any time by itsrespective optical fiber 36, and each of those small arcuate lengths canbe characterized as an active portion or a spacing guide portion. Asbest seen in FIGS. 8-10, the cross member 74 cooperates with the spacingguide portions to define what can be characterized as spacing aperturesthrough which the optical fibers 36 respectively extend. The spacingguide portions and spacing apertures move laterally with respect to oneanother as the guide cylinder 50 is rotated, as is best understood withreference to FIGS. 7-10, which sequentially illustrate rotationalpositions of the guide cylinder.

As best understood with reference to FIGS. 4 and 7-10, the rate at whichthe narrow guide grooves 60 a-f transition from the separation spacingS1 to the separation spacing S2, from the separation spacing S2 to theseparation spacing S3, and from the separation spacing S3 to theseparation spacing S4 is preferably sufficiently gradual so as not tocause the optical fibers 36 to be damaged by stress and strain when theoptical fibers 36 are moved between the first through fourthconfigurations.

As best understood with reference to FIGS. 6 and 8-10, the fabricatingassembly 70 is set up for operation by establishing the desired spacingbetween the optical fiber ribbons 36, which is achieved by placing thefabricating assembly 70 in the second configuration (FIG. 8), the thirdconfiguration (FIG. 9), or the third configuration (FIG. 9), or in anyof the other numerous configurations that are between the firstconfiguration (FIG. 7) and the fourth configuration. Thereafter, theguide cylinder 50 is preferably locked with a locking mechanism (notshown) so that the guide cylinder will not rotate relative to the crossmember 74. As best seen in FIG. 11, in accordance with the firstembodiment, the tape application assemblies 76 are placed in theirproximate positions by moving them toward one another so that theapplicator rollers 82 force the adhesive sides of the tape 80 onto orimmediately adjacent to the opposite sides of the narrow end 29 (FIG. 1)of the conventional multipitch optical fiber ribbon 26.

After the fabricating assembly 70 is fully set up for operation asdescribed above, the exposed array 34 of optical fibers 36 is advancedthrough the respective spacing guide portions of the narrow guidegrooves 60 a-f. As mentioned above, in each of the second through fourthconfigurations respectively illustrated by FIGS. 8-10, only a smallarcuate length of each of the narrow guide grooves 60 a-f is occupied atany time by the respective one of the optical fibers 36, and each ofthose small arcuate lengths can be characterized as an active portion ora spacing guide portion. In accordance with the first embodiment, theadvancing is achieved by moving the guide cylinder 50 relative to theoptical fibers 36, and preferably that movement is translational. Morespecifically, the advancing is achieved by moving the frame 72 along thetrack 83, as illustrated in FIG. 11. The frame 72 is one example of amoving device for advancing the optical fibers 36 in the longitudinaldirection through their respective spacing guide portions of the guidegrooves 60 a-f so that the spacing of the spacing guide portions isimparted upon portions of the optical fibers that are downstream fromthe guide cylinder 50.

As best seen in FIG. 11, as the frame 72 moves toward the upstreamholding device 84, the pieces of tape 80 are longitudinally applied tothe opposite sides of the exposed array 34 of optical fibers 36 that aredownstream from the guide cylinder 50 to form the wide section 30 of themultipitch optical fiber ribbon 20. Alternatively, one or more pieces ofthe tape 80 may be helically wrapped around the exposed array 34 ofoptical fibers 36 that are downstream from the guide cylinder 50 to formthe wide section 30 of the multipitch optical fiber ribbon 20. Theformed multipitch optical fiber ribbon 20 is removed from thefabrication assembly 70 by releasing the narrow section 26 from thedownstream holding device 88, releasing the array 34 of optical fibers36 from the upstream holding device 84, and moving the cross member 74to its remote position, which is illustrated by broken lines in FIG. 6.

In accordance with the first embodiment, the wide section 30 of themultipitch optical fiber ribbon 20 has the separation spacing S2 (FIGS.1, 3, and 8). Accordingly, in accordance with the first embodiment, whenthe fabricating assembly 70 is fully set up for operation it is in thesecond configuration, which is illustrated in FIG. 8.

A multipitch optical fiber ribbon of a second embodiment of the presentinvention is like the multipitch optical fiber ribbon 20 (FIG. 1) of thefirst embodiment, except that in the second embodiment the separationspacing S3 (FIG. 9) is defined between the optical fibers in the widesection (for example see the wide section 30 in FIGS. 1 and 3) of themultipitch optical fiber ribbon, and the wide section defines a greaterwidth than the width W2 (FIG. 1). In accordance with the, secondembodiment, when the fabricating assembly 70 is fully set up foroperation it, is in the third configuration, which is illustrated inFIG. 9.

A multipitch optical fiber ribbon of a third embodiment of the presentinvention is like the multipitch optical fiber ribbon 20 (FIG. 1) of thefirst embodiment, except that in the third embodiment the separationspacing S4 (FIG. 10) is defined between the optical fibers in the widesection (for example see the wide section 30 in FIGS. 1 and 3) of themultipitch optical fiber ribbon, and the wide section defines a greaterwidth than the width W2 (FIG. 1). In accordance with the thirdembodiment, when the fabricating assembly 70 is fully set up foroperation it is in the fourth configuration, which is illustrated inFIG. 10.

As best understood with reference to FIGS. 1-3, in accordance with afourth embodiment of the present invention, homogenous bonding material42 is substituted for the composite bonding material 44 of the widesection 30 of the multipitch optical fiber ribbon 20. In accordance withthe fourth embodiment, the tape application assemblies 76 illustrated inFIGS. 6 and 11 are replaced with conventional assemblies for applyingthe homogenous bonding material 42.

As best understood with reference to FIG. 11, in accordance with a fifthembodiment of the present invention, the frame 72 of the fabricatingassembly 70 is stationery, and the exposed array 34 of optical fiberribbons 36 are drawn past the guide cylinder 50 during the formation ofthe wide section 30 of the multipitch optical fiber ribbon 20. This isacceptably achieved by paying the exposed array 34 of optical fiberribbons 36 off of an upstream supply roll (not shown) and wrapping theformed multipitch optical fiber ribbon 20 onto a downstream take up roll(not shown).

Whereas the present invention is described above in the context offorming the multipitch optical fiber ribbon 20 from a previously formedconventional multipitch optical fiber ribbon 26, it is within the scopeof the present invention for the fabricating assembly 70 to be used toconstruct a multipitch optical fiber ribbon or a single-pitch opticalfiber ribbon from an array of optical fibers that were not previouslyassociated with an optical fiber ribbon, as should be understood bythose of ordinary skill in the art in view of this disclosure.

Many other modifications and other embodiments of the invention willcome to mind to one skilled in the art to which this invention pertainshaving the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Therefore, it is to beunderstood that the invention is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

That which is claimed:
 1. An assembly for establishing lateral spacingbetween a plurality of longitudinally extending optical fibers, theassembly comprising: a wall that extends generally arcuately about anaxis that extends in a generally lateral direction, wherein the wallfurther extends generally in the lateral direction, the wall comprisesan outer surface that generally extends generally arcuately about theaxis and in the lateral direction, the wall defines a plurality ofgrooves that are open at the outer surface, each groove extendsgenerally arcuately about the axis, the grooves are spaced apart fromone another in the lateral direction, and the spacing between thegrooves varies with respect to an arcuate direction that is definedabout the axis.
 2. The assembly of claim 1, further comprising a frame,wherein the wall is pivotally connected to the frame for pivoting aboutthe axis.
 3. The assembly of claim 1, further comprising marksdesignating intervals along the grooves in the arcuate direction.
 4. Theassembly of claim 1, wherein each of the grooves defines a width thatgenerally extends in the lateral direction and is slightly greater thanthe diameter of the optical fibers.
 5. The assembly of claim 1, whereineach of the grooves defines a depth that generally extends in the radialdirection with respect to the axis and is slightly greater than thediameter of the optical fibers.
 6. The assembly of claim 1, furthercomprising a cross member in close proximity to the outer surface andextending generally in the lateral direction across the grooves so thatthe cross member cooperates with portions of the wall that define thegrooves to define a plurality of spacing apertures capable ofrespectively receiving the optical fibers.
 7. The assembly of claim 6,further comprising a frame, wherein the cross member is connected to theframe and the wall is pivotally connected to the frame for pivotingabout the axis and relative to the cross member.
 8. The assembly ofclaim 1, wherein the grooves are relatively narrow grooves and the wallfurther defines a relatively wide groove that is wider than therelatively narrow grooves, wherein the wide groove is open at the outersurface, the wide groove extends generally arcuately about the axis, andthe narrow grooves are contiguous with and generally extend in thearcuate direction away from the wide groove, and the narrow groovesdiverge as they extend generally in the arcuate direction away from thewide groove.
 9. The assembly of claim 8, wherein the wide groove definesa width that generally extends in the lateral direction and is slightlygreater than the product of the number of the optical fibers and thediameter of the optical fibers.
 10. The assembly of claim 8, wherein thewide groove defines a depth that generally extends in the radialdirection with respect to the axis and is slightly greater than thediameter of the optical fibers.
 11. An assembly for fabricating anoptical fiber ribbon from a plurality of optical fibers that extend in alongitudinal direction, the assembly comprising: a spacing devicecomprising a plurality of spacing guides that are spaced apart from oneanother in a lateral direction that is generally perpendicular to thelongitudinal direction, wherein each spacing guide is operative forrespectively receiving and guiding an optical fiber of the opticalfibers so that the optical fiber exits from the spacing guide at anoutlet of the spacing guide, and the spacing device is operative to varythe spacing between the outlets of the spacing guides in the lateraldirection; a moving device for advancing the optical fibers generally inthe longitudinal direction through their respective spacing guides sothat the spacing of the spacing guides is imparted upon portions of theoptical fibers that are downstream from the spacing guides; and abonding device positioned downstream from the spacing guides andoperative for applying bonding material to the portions of the opticalfibers that are downstream from the spacing guides so that the bondingmaterial bonds the portions of the optical fibers that are downstreamfrom the spacing guides together to form the optical fiber ribbon,wherein the assembly is capable of fabricating optical fiber ribbonswith different pitches since the spacing device is operative to vary thespacing between the outlets of the spacing guides in the lateraldirection.
 12. The assembly of claim 11, wherein the spacing devicecomprises a wall that generally extends in the lateral direction andgenerally extends in the longitudinal direction, the wall comprises anouter surface that extends generally in the lateral direction andgenerally in the longitudinal direction, the spacing guides are aplurality of surfaces of the wall that define a plurality of groovesthat are open at the outer surface of the wall and generally extend inthe longitudinal direction, the grooves are spaced apart from oneanother in the lateral direction, and the spacing between the groovesvaries in the longitudinal direction.
 13. The assembly of claim 12,wherein the outer surface of the wall extends generally arcuately aboutan axis that extends generally in the lateral direction and the groovesextend generally arcuately about the axis.
 14. A method of manufacturingan optical fiber ribbon, comprising: advancing a plurality opticalfibers that extend in a longitudinal direction along a plurality oftravel paths, wherein the travel paths diverge from one another in alateral direction that is generally perpendicular to the longitudinaldirection so that as the optical fibers are advanced the optical fibersbecome further spaced apart from one another in the lateral direction sothat the lateral spacing between the optical fibers changes from a firstspacing to a second spacing that is greater than the first spacing; andmaintaining the second spacing between the optical fibers by bonding theoptical fibers together.
 15. The method of claim 14, wherein theadvancing step comprises the step of moving a guide member relative tothe optical fibers.
 16. The method of claim 15, wherein the moving stepcomprises rotating the guide member about an axis.
 17. The method ofclaim 14, wherein: the advancing step comprises the step of rotating aguide member relative to the optical fibers; and the method furthercomprises the step of translating the guide member relative to theoptical fibers so that the maintaining step is performed over alongitudinally extending section of the optical fiber ribbons.
 18. Themethod of claim 14, further comprising the steps of: providing anoptical fiber ribbon comprising: an array of a plurality of opticalfibers that extend longitudinally and are laterally adjacent, whereinthe array comprises a longitudinally extending first segment and alongitudinally extending second segment, and bonding material that bondsthe optical fibers together along the longitudinally extending firstsegment of the array and along the longitudinally extending secondsegment of the array; and removing bonding material from the secondsegment of the array to expose portions of the optical fibers, whereinthe advancing and maintaining steps are carried out on the portions ofthe optical fibers that are exposed by the removing step.